L2/13-185
Re: Address issue with decorated Latin characters
To: UTC
Source: Mark Davis
Date: 2013-10-06

We changed the following characters to Uppercase, but didn't add them to Alphabetic. That showed up in the invariant tests, because it breaks a stability constraint. So the change was pulled from the release.
  • 1F130..1F149   # [26] (🄰..🅉)  SQUARED LATIN CAPITAL LETTER A..SQUARED LATIN CAPITAL LETTER Z
  • 1F150..1F169   # [26] (🅐..🅩)  NEGATIVE CIRCLED LATIN CAPITAL LETTER A..NEGATIVE CIRCLED LATIN CAPITAL LETTER Z
  • 1F170..1F189   # [26] (🅰..🆉)  NEGATIVE SQUARED LATIN CAPITAL LETTER A..NEGATIVE SQUARED LATIN CAPITAL LETTER Z
We have to decide what to do for Unicode 7.0. I think we have two choices:
A. Make them both Uppercase and Alphabetic
Advantage: less confusing for users and programmers, since it removes the inconsistency with U+24B6 ( Ⓐ ) CIRCLED LATIN CAPITAL LETTER A (the latter is both Uppercase and Alphabetic).
or
B. Leave them as they are in 6.3 (neither Alphabetic nor Uppercase).
Advantage: if we were ever to add the lowercase Squared/Negative Latin letters, we could not make them casing pairs.